1. Field of the Invention
Interferon is a glycoprotein whose synthesis is induced in cultured cells principally by viruses or by natural or synthetic double stranded RNAs. This induction requires de novo macromolecular synthesis as indicated by its sensitivity to inhibitors of both RNA and protein synthesis. interferon is believed to be secreted by the induced cell, whereby the secreted interferon interacts with other cells resulting in the establishment, maintenance and expression of an intracellular antiviral state.
The amount of interferon which is produced is exquisitely small, so that its isolation has been extremely elusive. The primary source of human interferon is from Helsinki, Finland, where partially purified human leukocyte interferon is obtained from blood given by blood donors. Because of the limited source of interferon, and the difficulties in purification and concentration, the cost of interferon is prohibitively high. In view of its antiviral nature and its acceptability by a mammalian host, the production of interferon in useful amounts holds great promise for its use in treatment of a wide variety of viral induced disorders or malignancies.
2. Description of the Prior Art
U.S. Pat. No. 3,699,222 teaches the production of interferon by induction of monolayer cell cultures with virus. Jarvis and Colby, Cell 14, 355 (1978) disclose the isolation and characterization of a mutant 3T6 cell engaged in the semiconstitutive synthesis of interferon. Jarvis, et al. Somatic Cell Genetics 4, 677 (1978) disclose the hybridization of murine cells with expression of a dominant mutation affecting the regulation of interferon production.